• Title, Summary, Keyword: Composite Structure

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Design Optimization of Blast Resistant CFRP-steel Composite Structure Based on Reliability Analysis (신뢰성 해석에 의한 내폭 CFRP-steel 복합구조의 최적화 설계)

  • Kim, Jung Joong;Noh, Hyuk-Chun
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.3 no.4
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    • pp.10-16
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    • 2012
  • This study presents the effectiveness of a composite structure at improving blast resistance. The proposed composite structure consists of carbon fiber reinforced polymer (CFRP) and steel layers. While CFRP layer is used for blast energy reflection due to its high strength, steel layer is used for blast energy absorption due to its high ductility. A dynamic model is used to simulate the elastoplastic behavior of the proposed composite structure subject to blast load. Considering the magnitude variations of a blast event, the probability of failure of each layer is evaluated using reliability analysis. By assigning design probability of failure of each layer in the composite structure, the thickness of layers is optimized. A case study for the design of CFRP-steel composite structure subjected to an uncertain blast event is also presented.

A Study on Repair Technique after Damage of Aircraft Sandwich Composite Structure (항공기 기체에 적용된 샌드위치 복합재 구조의 손상 후 수리 방안 연구)

  • Park, Hyunbum;Kong, Changduk
    • Journal of Aerospace System Engineering
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    • v.7 no.1
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    • pp.39-43
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    • 2013
  • In this study, damage assesment and repair technique of aircraft adopted on Sandwich composite structure were performed. The sandwich composite structure were damaged by drop weight type impact test machine. The damaged sandwich composite structure was repaired using external patch repair method after removing damaged area. This study presents comparison results of the experimental investigation between the impact damaged and the repaired specimen.

Structural Behavior of Composite Slab toNuclear Power Structure under Reversed Cyclic Loads (반복하중을 받는 원자력 구조물 합성 바닥판의 구조적 거동)

  • 김정혁;김강식;김우범;정하선;이광수;신성우
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.629-634
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    • 2000
  • Comparing with single structure constructed with reinforced concrete or steel, composite structures have a great advantage. However, in case of nuclear power structure, the application of a conventional single structure (reinforced concrete or steel structure) inflicts a heavy loss on a economical and constructive efficiency. But, the application of composite slab to nuclear power structure could compensate these deficiency. Therefore, in this study, the structural behavior of composite slab in nuclear power structure is observed to assure economical and constructive efficiency.

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Feasibility study of bonding state detection of explosive composite structure based on nonlinear output frequency response functions

  • Si, Yue;Zhang, Zhou-Suo;Wang, Hong-fang;Yuan, Fei-Chen
    • Steel and Composite Structures
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    • v.24 no.4
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    • pp.391-397
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    • 2017
  • With the increasing application of explosive composite structure in many engineering fields, its interface bonding state detection is more and more significant to avoid catastrophic accidents. However, this task still faces challenges due to the complexity of the bonding interface. In this paper, the concept of nonlinear output frequency response functions (NOFRFs) is introduced to detect the bonding state of explosive composite structure. The NOFRFs can describe the nonlinear characteristics of nonlinear vibrating system. Because of the presence of the bonding interface, explosive composite structure itself is a nonlinear system; when bonding interface of the structure is damaged, its dynamic characteristics show enhanced nonlinear characteristic. Therefore, the NOFRFs-based detection index is proposed as indicator to detect the bonding state of explosive composite pipes. The experimental results verify the effectiveness of the detection approach.

Dynamic Characteristics Modification of Damaged Composite Structure Using MFC and Active Control Algorithm (MFC와 능동 제어를 이용한 손상된 복합재의 동적 특성 복원)

  • Sohn, Jung Woo;Kim, Heung Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.12
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    • pp.1066-1072
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    • 2013
  • In this work, active control algorithm is adopted to reduce delamination effects of the damaged composite structure and control performance with MFC actuator is numerically evaluated. Finite element model for the damaged composite structure with piezoelectric actuator is established based on improved layerwise theory. In order to achieve high control performance, MFC actuator, which has increased actuating force, is considered as a piezoelectric actuator. Mode shapes and corresponding natural frequencies for the damaged smart composite structure are studied. After design and implementation of active controller, dynamic characteristics of the damaged smart composite structure are investigated.

Active Control of Damaged Composite Structure Using MFC Actuator (MFC를 이용한 손상된 복합재의 능동제어)

  • Sohn, Jung Woo;Kim, Heung Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.535-540
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    • 2013
  • In this work, active control algorithm is adopted to reduce delamination effects of the damaged composite structure and control performance with MFC actuator is numerically evaluated. Finite element model for the damaged composite structure with piezoelectric actuator is established based on improved layerwise theory. In order to achieve high control performance, MFC actuator, which has increased actuating force, is considered as a piezoelectric actuator. Mode shapes and corresponding natural frequencies for the damaged smart composite structure are studied. After design and implementation of active controller, dynamic characteristics of the damaged smart composite structure are investigated.

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Mechanical behavior of composite gel periodic structures with the pattern transformation

  • Hu, Jianying;He, Yuhao;Lei, Jincheng;Liu, Zishun;Swaddiwudhipong, Somsak
    • Structural Engineering and Mechanics
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    • v.50 no.5
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    • pp.605-616
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    • 2014
  • When the periodic cellular structure is loaded or swelling beyond the critical value, the structure may undergo a pattern transformation owing to the local elastic instabilities, thus leading to structural collapse and the structure changing to a new configuration. Based on this deformation-triggered pattern, we have proposed the novel composite gel materials. This designed material is a type of architectural material possessing special mechanical properties. In this study, the mechanical behavior of the composite gel periodic structure with various gel inclusions is studied further through numerical simulations. When pattern transformation occurs, it results in a different elastic relationship compared with the material at untransformed state. Based on the obtained nominal stress versus nominal strain behavior, the Poisson's ratio and corresponding deformed structure patterns, we investigate the performance of designed composite materials and the effects of the uniformly distributed gel inclusions on composite materials. A better understanding of the characteristics of these composite gel materials is a key to develop its potential applications on new soft machines.

Experimental Study on Shape Control of Smart Composite Structure with SMA actuators (SMA 작동기를 이용한 스마트 복합재 구조의 형상 제어에 관한 실험적 연구)

  • Yang Seung-Man;Roh Jin-Ho;Han Jae-Hung;Lee In
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.127-130
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    • 2004
  • In this paper, active shape control of composite structure actuated by shape memory alloy (SMA) wires is presented. Hybrid composite structure was established by attaching SMA actuators on the surfaces of graphite/epoxy composite beam using bolt-joint connectors. SMA actuators were activated by phase transformation, which induced by temperature rising over austenite finish temperatures. In this paper, electrical resistive heating was applied to the hybrid composite structures to activate the SMA actuators. For faster and more accurate shape or deflection control of the hybrid composite structure, PID feedback controller was designed from numerical simulations and experimentally applied to the SMA actuators.

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Studies on restoring force model of concrete filled steel tubular laced column to composite box-beam connections

  • Huang, Zhi;Jiang, Li-Zhong;Zhou, Wang-Bao;Chen, Shan
    • Steel and Composite Structures
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    • v.22 no.6
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    • pp.1217-1238
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    • 2016
  • Mega composite structure systems have been widely used in high rise buildings in China. Compared to other structures, this type of composite structure systems has a larger cross-section with less weight. Concrete filled steel tubular (CFST) laced column to box-beam connections are gaining popularity, in particular for the mega composite structure system in high rise buildings. To enable a better understanding of the destruction characteristics and aseismic performance of these connections, three different connection types of specimens including single-limb bracing, cross bracing and diaphragms for core area of connections were tested under low cyclic and reciprocating loading. Hysteresis curves and skeleton curves were obtained from cyclic loading tests under axial loading. Based on these tested curves, a new trilinear hysteretic restoring force model considering rigidity degradation is proposed for CFST laced column to box-beam connections in a mega composite structure system, including a trilinear skeleton model based on calculation, law of stiffness degradation and hysteresis rules. The trilinear hysteretic restoring force model is compared with the experimental results. The experimental data shows that the new hysteretic restoring force model tallies with the test curves well and can be referenced for elastic-plastic seismic analysis of CFST laced column to composite box-beam connection in a mega composite structure system.

Design and Analysis of Composite Surface-Antenna-Structure for the Satellite Communication (위성통신을 위한 복합재료 표면안테나 구조의 설계 및 해석)

  • 유치상;황운봉;박현철;박위상
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.1-4
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    • 2002
  • The present study aims to design a multiplayer microstrip antenna with composite sandwich construction and to estimate structural behavior of this multiplayer structure for the next generation of structural surface technology. This is termed Surface-Antenna-Structure indicating that structural surface becomes antenna. Constituent materials were selected considering electrical properties as well as mechanical properties. For the antenna performance, antenna elements inserted into structural layers were designed for satellite communication at a resonant frequency of 12.5 GHz and final demonstration article was $16\times16$ array antenna. From electrical measurements it was shown that antenna performances were in good agreement with design requirements. Structural analysis showed this antenna structure was well designed for the mechanical rigidity. All constituent materials were characterized independently. The SAS concept is the first serious attempt at integration for both antenna and composite engineers and promises innovative future communication technology.

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